This invention relates to an index-feed processing system for performing punching, spinning, cutting, laminating and other processing operations on a piece of work by carrying out the processing operation of each process in a set of apparatuses, indexing the workpiece sequentially to the succeeding process to add a new processing operation onto the workpiece, and completing the entire processing operations in the final process.
Manufacturing a sheet metal product of a predetermined shape by performing punching, spinning, compressing and other processing operations on a sheet metal material comprising a structural material, such as a steel sheet has heretofore normally involved several processes. When a large quantity of such sheet metal products are involved, a commonly used manufacturing practice is such that a processing operation of each manufacturing process or stage is performed individually on a workpiece in a single piece of processing die, the workpiece is indexed sequentially to the next step to add a new processing operation, and the processing operation is completed in the final stage. This type of processing die, which is called the progressive die, has the advantage of extremely high efficiency since a piece of sheet metal product can be obtained in each stamping operation of a press, for example.
The conventional type of index-feed processing die as described earlier has the advantages of high production rate, short delivery time from the input of a workpiece to the completion of the entire processing operations, less work-in-process required in the intermediate steps of a press working process, and mass production with a small number of operators. It has the following problems, on the other hand. That is, since its construction involves multiple pairs of punch and die in a single mold, the mold construction is extremely complex, requiring high-precision mold manufacturing technology, long manufacturing period, and an enormous amount of manufacturing cost.
Furthermore, repairing and/or adjustment of a partially damaged mold requires disassembly of the entire mold. These complex operations require a large amount of time and labor. In addition, when a system of manufacturing special molds has to be adopted to meet slightly different requirements in terms of the shape and dimensions of specific workpieces in a large-item small-scale production system, mold cost is unwantedly increased, making it impossible to adopt the so-called flexible manufacturing system (FMS) which is increasing in popularity in recent years.
To solve these problems, the present applicant filed patent applications for index-feed metal processing systems of a simple construction that can accommodate partial adjustment (Japanese Patent Application No. Hei-2(1990)-121760 now Japanese Pat. No. 4-17930, Japanese Patent Application No. Hei-2(1990)-121761 now Japanese Patent 4-17998, etc., for example).
FIG. 11 is a perspective view of an example of an index-feed metal processing system on which the present invention is based. In FIG. 11, numerals 100xcx9c500 denote processing units disposed on a base 1 at intervals of 2 P (P denotes the feeding pitch of a workpiece (not shown)), for example, in the feeding direction of the workpiece. Each of the processing units 10xcx9c500 has a pair of punch and die corresponding to a plurality of processing processes, which will be described in the following, taking the processing unit 100 as an example.
Numeral 101 refers to a processing unit body formed into a virtually U shape, having a dovetail 102 integrally formed at the lower end thereof that engages with a dovetail groove 103 provided on the base 1 so that adjustment can be made to permit the body 101 to move in the feeding direction of the workpiece while restricting the movement of the body 101 in the direction normal to the feeding direction of the workpiece. Numeral 104 refers to a movement adjusting device, and 105 to a clamp. Numeral 106 refers to a hydraulic cylinder provided on the upper end of the body 101, and 107 to a position measuring device provided on the side surface of the hydraulic cylinder 106.
Numeral 108 refers to a cassette formed into a virtually U shape, provided detachably on the body 101 and having a punch or die (neither of them shown) provided vertically movably on the upper part thereof, and a die or punch that is the counterpart of the aforementioned punch or die provided on the lower part thereof. The cassette 108 is positioned by causing it to engage with positioning members 309 and 310, as shown in the processing unit 300 in the figure. Numeral 111 refers to a clamp screw.
That is, the cassette 108 can be positioned by mounting it on the body 101 via the positioning members (not shown. Refer to numerals 309 and 310 in the processing unit 300), and locked in position by tightening the clamping screw 111. After the cassette 108 has been locked, an actuating rod (not shown) of the hydraulic cylinder 106 is connected to the aforementioned vertically movable punch or die.
FIG. 12 is a diagram of assistance in explaining the state of processing the workpiece, (a) being a plan view and (b) a cross-sectional view thereof. Like parts are shown by like numerals used in FIG. 11. In FIG. 12, numeral 2 refers to a workpiece that is indexed intermittently at a pitch P in the direction shown by an arrow. That is, the workpiece 2 is indexed between a pair of punch and die provided on the cassette 108 (the same applies to the other cassettes), as shown in FIG. 11. In FIGS. 11 and 12, the processing units 100xcx9c500 are formed in such a manner as to correspond to a processing process for providing pilot holes 3, a processing process for providing arc-shaped slits 4, and first through third drawing processes.
The processing unit 100 has a punch and die for providing pilot holes 3, and guides (not shown) for engaging with the pilot holes 3 provided at position P on the downstream side in the feeding direction of the workpiece 2. As a result, as the processing unit 100 is operated and the pilot holes 3 are provided one after another, the guides are engaged with the pilot holes 3, based on which subsequent positioning and processing are performed to prevent the workpiece 2 from unwantedly shifting in position, thereby maintaining precision.
Next, arc-shaped slits 4 are machined in the processing unit 200, and a first drawing operation is performed in the processing unit 300 to form cup-shaped projections 5 on the workpiece 2, while the arc-shaped slits 4 expands in width, turning into arc-shaped grooves 6. In the processing unit 400, moreover, a second drawing operation is performed and flange holes 7 are machined, with the result that the height of the projections is increased. In the processing unit 500, a third drawing operation is carried out to form the height of the projections 5 into a predetermined size.
Subsequently, trimming and other operations are performed, though not shown in the figure, to obtain a sheet metal product of a predetermined shape. Needless to say, positioning is carried out in the processing units 200xcx9c500, too, to maintain predetermined precision by providing guides for engaging with the pilot holes 3.
The index-feed processing system of the aforementioned construction has the advantages of a simpler construction than that of the conventional progressive dies, ease of manufacture, and high-efficient processing accomplished even in a large-item small-scale production system. But it has the following disadvantages.
That is, since the conventional index-feed processing system normally involves workpiece of a strip shape, most system of this type are chiefly designed to carry out bending, drawing, blanking, piercing and other sheet-metal processing operations. It is usually difficult for such index-feed metal processing systems to perform machining operations, such as threading, for example, on part of a product. In such a case, therefore, threading and other machining operations are additionally carried out upon completion of the index-feed metal processing operations, resulting in increased cost.
The index-feed metal processing system usually involves a large number of products per production lot since products obtained by index-feed metal processing are mostly small items, and are manufactured continuously. Additional machining on such large-volume products not only requires special-purpose processing jigs but also extra time and labor for mounting and removing products on and from such jigs. This not only leads to increased processing cost, but involves difficulty in improving dimensional accuracy of processed parts due to variability of datum surface.
To solve these problems, the present applicant filed patent applications on inventions for providing a machining means on the intermediate part of a given processing unit in such a manner as to be accessible and detachable to and from the workpiece, and for providing given processing units on a multi-spindle machining unit having a plurality of spindles so as to permit a plurality of machining operations (Japanese Patent Application Nos. Hei-3(1991)-269833 and Hei-6(1994)-169120).
With the above-mentioned construction, a long-sized, strip- or hoop-shaped workpiece incorporating therein different portions to be formed into products can be subjected to a plurality of machining ranging from internal and external threading, to drilling, countersinking, chamfering, spot facing, staking, marking, etc. simultaneously in a single process, thereby reducing manhours and improving dimensional accuracy.
In the aforementioned system, however, there still remain several problems. That is, since the aforementioned machining means or multi-spindle machining unit has a separate construction from that of the press working unit, separate machining units have to be provided every time different types of machining operations are to be carried out. This lack of interchangeability in the entire system necessitates replacement of the entire index-feed processing system, requiring excess time and labor for mounting and removing the system.
Machining with the aforementioned machining unit generally takes longer hours compared with press working, extending the machining tact time for the entire system, leading to lowered productivity.
To machine a workpiece having a plurality of portions being machined, on the other hand, a machining center having a plurality of machining tools is especially effective. Even in this case, machining time for each process or stage tends to become comparatively longer. Furthermore, when the machining process is divided into a plurality of processes, a plurality of expensive machining centers have to be provided, increasing equipment cost for the entire system.
The present invention is intended to overcome the problems inherent in the prior art, and it is an object of the present invention to provide an index-feed processing system that can reduce processing cost of products involving a plurality of machining processes.
To solve the above problems, the first invention adopts a technical means involving an index-feed processing system where a plurality of processing units having cassettes incorporating machining means and detachably mounted on a unit body are disposed at intervals of mP (m being a given positive integer, and P being an index-feeding pitch of workpiece) in the longitudinal feeding direction of a long-sized workpiece corresponding to a plurality of processing processes so that the processing processes can be sequentially performed with the processing units on the index-fed workpiece; the improvement comprising
the unit body formed by a base plate, a support plate provided at a predetermined distance from the base plate, a slider provided between the base plate and the support plate movably in a direction orthogonally intersecting the base plate and the support plate, and a drive means for driving the slider, and
the processing units formed as machining units so that machining operations can be performed continuously by controlling the movement of the slider.
The second invention adopts a technical means involving an index-feed processing system where a plurality of processing units having cassettes incorporating machining means and detachably mounted on a unit body are disposed at intervals of mP (m being a given positive integer, and P an index-feeding pitch of workpiece) in the longitudinal feeding direction of a long-sized workpiece corresponding to a plurality of processing processes so that the processing processes can be sequentially performed with the processing units on the index-fed workpiece; the improvement comprising
the unit body formed by a base plate, a support plate provided at a predetermined distance from the base plate, a slider provided between the base plate and the support plate movably in a direction orthogonally intersecting the base plate and the support plate, and a drive means for driving the slider, and
a given number of the processing units formed as machining units and the other processing units formed as press working units
so that processing, including machining and press working operations, can be performed continuously by controlling the movement of the slider.
In the above inventions, the base plate and the support plate may be disposed in parallel with the horizontal plane, and the slider may be formed movably in the vertical direction.
Furthermore, the drive means in the above inventions may be a mechanism including a servomotor and a screw pair. In this case, the screw pair may be a ball screw.
Moreover, the slider in the above inventions may be formed in such a manner as to slide along a guide bar provided between the base plate and the support plate.
Furthermore, the cassette of the machining unit in the above inventions may be formed by a holder that can detachably and rotatably hold a tool, and an XY table for moving the holder in the direction orthogonally intersecting the traveling direction of the slider. In this case, the drive means of the XY table may be formed by a linear motor.